The oscillating flow regenerative heat engine disclosed in PTL 1 and the rotary Stirling engine disclosed in PTL 2 have conventionally been known as examples of Stirling engines including: a displacer body unit having a displacer cylinder in which a working gas and a movable displacer are accommodated; a cooling and heating working unit having a heating unit that heats a first side of the displacer cylinder and a cooling unit that cools a second side of the displacer; a displacer-driving actuator that moves the displacer; and a power output unit having a power cylinder containing a power piston which is moved by the effect of volume change of the working gas in the displacer cylinder, in particular a Stirling engine whose displacer is a rotary displacer having a circular cylindrical shape and a central axis that rotates.
The oscillating flow regenerative heat engine disclosed in PTL 1 is intended to prevent mixture of gases in a plurality of cycles and to uniformize working gas passageways. Specifically, in an oscillating flow regenerative heat engine such as a Stirling refrigeration machine wherein the working gas is sealed inside of a system composed of a compression space of a compressor, a radiator, a regenerator, a heat absorber, and an expansion space of an expander, and the working gas is oscillated when the volume of the compression space and the volume of the expansion space are periodically changed with a predetermined phase difference in order to achieve a cooling capacity at a predetermined temperature from the heat absorber, the compressor is composed of a housing, rotors rotatably mounted in the internal space of the housing, and a plurality of vanes energized in the radially inward direction of the internal space, having tip end parts slidably kept into contact with outer circumferential surfaces of the rotors at all times, and arranged at predetermined intervals in the circumferential direction, and at least one of a plurality of volume-variable working spaces formed by sectioning the internal space by the rotors and the plurality of vanes is applied as the compression space.
Further, the rotary Stirling engine disclosed in PTL 2 is intended to provide a Stirling engine with high thermal efficiency by reducing wasteful heat flows while a working fluid moves in a γ Stirling engine using a rotary displacer. Specifically, along with the rotary displacer, a heat-absorbing regenerator and a heat-releasing regenerator which are fixed to both ends of a sliding heat pipe are internally placed in a displacement chamber. When the rotary displacer is rotated, the working fluid in the displacement chamber moves through the gap between the heat-absorbing regenerator and the heat-releasing regenerator to exchange heat therebetween. The heat transfer between the heat-absorbing regenerator and the heat-releasing regenerator is performed by the sliding heat pipe. The heat energy stored in the heat-absorbing regenerator is returned from the heat-releasing regenerator to the working fluid after a half cycle to increase the heat efficiency. The collision between the rotary displacer and the heat-absorbing regenerator and the heat-releasing regenerator is avoided by the cam mechanism.